I just don't understand the First Order. It's entirely unclear how much power they have, how they got that power, what their goal is, why they can or can't do certain things, etc. It's unclear in TFA, it's unclear in TLJ, and it seems different in both, making it even more confusing. It's hard to care about the power struggle between Hux and Kylo, for example, when I don't even know how widespread the First Order's influence goes or what their goal is. They seem like bad guys for the sake of having bad guys, and I can't figure out what the protagonists want/need to do to oppose the villains if I don't understand the villains at least a little bit to begin with.
In Solo, I like that the villain motivation is clear, even if it is mostly based on just greed. We understand what the antagonists want, we know how much power they have currently and how much they want to get, we understand why the protagonists are against them - it all makes sense. Yes, they add in a few extra layers that give some intrigue and depth to them, which is good, but it's still pretty clear what sort of power the villains have and what they're after. It makes the plot much cleaner and easier to follow. Instead of trying to puzzle out what undisclosed motivations everyone has, I can just sit back and enjoy the actual story.